Preparation and application of carbon dot composite system for self-enhanced targeting tumor blood vessels

Abstract

The invention discloses preparation and application of a carbon dot composite system of a self-enhanced targeting tumor vessel, belongs to the technical field of medicines, and particularly relates to preparation of the carbon dot composite system of the self-enhanced targeting tumor vessel and application of the carbon dot composite system in the aspects of tumor cascade catalytic treatment and photo-thermal treatment. The carbon dot composite system is composed of metal ion doped red light nano enzyme carbon dots, glucose oxidase, arginine and a tumor vessel site targeting ligand. The tumor blood vessel site is targeted through the targeting ligand, depolymerization is carried out in a subacid environment and under the photo-thermal heating effect, glucose oxidase consumes glucose in the tumor site to generate hydrogen peroxide, and hunger treatment is carried out while more. OH is generated. According to the carbon dot composite system of the self-enhanced targeted tumor blood vessel, cascade catalytic treatment, photo-thermal treatment and gas treatment are combined to achieve efficient tumor growth inhibition, and important reference is provided for multi-mode tumor treatment.

Description

Technical Field

[0001] The present invention belongs to the field of medical technology, and specifically relates to the preparation of a self-enhanced carbon dot composite system targeting tumor blood vessels, and its application in the preparation of synergistic therapeutic drugs for tumor cascade catalytic therapy, photothermal therapy and gas therapy. Background Art

[0002] Cancer is one of the most serious diseases currently threatening human health. It is caused by the uncontrolled proliferation of abnormal cells, which invade and destroy surrounding healthy tissue, resulting in severe consequences. Effective drug delivery to tumor sites is crucial for achieving effective cancer treatment. With the advancement of oncology and nanoformulations, the addition of targeting heads to nanoformulations can achieve active targeting of drugs, thereby increasing their accumulation at the tumor site. Traditional targeting heads, such as hyaluronic acid and folic acid, can achieve tumor targeting to a certain extent, but they still have significant challenges. For example, CD44 receptors and folate receptors are also expressed on the surface of normal liver cells and healthy kidney tissue, resulting in only a small fraction of the drug being targeted. Furthermore, traditional targeting ligand targeting strategies are mostly "one-shot targeting," meaning that a single nanoformulation achieves the entire targeting process once, resulting in low overall targeting efficiency. Therefore, there is an urgent need to develop newer targeting strategies to improve targeting efficiency and achieve more precise cancer treatment.

[0003] Endothelial cells in tumor sites are activated by various factors (tumor necrosis factor-α, reactive oxygen species, hypoxia, etc.), subsequently expressing large amounts of P-selectin on their cell membrane surfaces. Therefore, it is envisioned that this could be used as a target for specific targeting of tumor sites and the design of a new targeting system. Fucoidan, a major component of brown algae, is a natural ligand for P-selectin and has a strong affinity for it, enabling targeted targeting of activated endothelial cells. Carbon dots are a novel carbon nanoluminescent material with the advantages of low biotoxicity, ease of surface modification, and fluorescence emission. Compared with traditional carbon dots that emit blue or green light, red-emitting carbon dots significantly avoid interference from background fluorescence from some tissue proteins, thereby achieving better tracking effects. Some carbon dots also exhibit nanozyme activity, increasing intracellular ROS levels and enhancing oxidative stress through the activity of various enzymes.

[0004] Vascular endothelial cells express P-selectin in response to ROS stimulation, and fucoidan can bind to P-selectin to target activated endothelial cells. Therefore, red-light-emitting carbon dots with nanozyme activity and fucoidan are designed as the key to the system, achieving a stronger tumor-targeting effect, which is of great significance for clinical tumor treatment. Summary of the Invention

[0005] The purpose of the present invention is to construct a self-enhanced carbon dot composite system that targets tumor blood vessels, through the targeted activation of vascular endothelial cells by fucoidan and the metal ion-doped red light carbon dots (carbon dot nanozymes) to produce ROS to stimulate vascular endothelial cell activation, thereby achieving self-enhanced targeted cascade catalytic therapy / photothermal therapy / gas therapy for synergistic anti-tumor effects.

[0006] The technical solutions adopted in the present invention are as follows:

[0007] The self-enhanced tumor vascular targeted carbon dot composite system has pH-responsive drug release capability and synergistic enhancement of photothermal therapy, cascade catalytic therapy, and gas therapy under near-infrared irradiation.

[0008] Preferably, the self-enhanced tumor vascular targeting carbon dot composite system consists of photothermal responsive carbon dot nanozyme, glucose oxidase (GOx), tumor site vascular targeting ligand and arginine.

[0009] Preferably, the photothermal responsive carbon dot nanozyme is formed by carbonization polymerization of citric acid, urea, disodium ethylenediaminetetraacetic acid, and metal ions, wherein the metal ions are Cu + 、Cu 2+ 、Fe 2+ 、Fe 3+ 、Mn 2+ One of them.

[0010] Preferably, the tumor site vascular targeting ligand is fucoidan.

[0011] The method for preparing the self-enhanced tumor vascular targeting carbon dot composite system of the present invention comprises the following steps:

[0012] (1) Preparation of metal ion-doped carbon dot nanozymes: Citric acid, urea, disodium ethylenediaminetetraacetic acid, and a metal ion precursor were dissolved in a formic acid solution, ultrasonically dispersed, and then placed in a polytetrafluoroethylene bottle and placed in a muffle furnace for reaction. After the reaction, the reaction solution was mixed with ethanol and centrifuged. The supernatant was discarded and the precipitate was collected to obtain the metal ion-doped carbon dot nanozymes.

[0013] (2) Preparation of carbon dot-glucose oxidase complex system (FG): Metal ion-doped carbon dot nanozyme is mixed with glucose oxidase, and the unreacted metal ion-doped carbon dot nanozyme is removed by centrifugal ultrafiltration to obtain the carbon dot-glucose oxidase complex system.

[0014] (3) Preparation of arginine-coated composite system (FGA): The carbon dot-glucose oxidase composite system was added to the arginine solution, mixed evenly and then ultrafiltered to obtain the arginine-coated composite system.

[0015] (4) Preparation of fucoidan-coated multifunctional nanozyme targeting tumor vascular sites: The arginine-coated composite system is added to the fucoidan solution and incubated together and then ultrafiltered to obtain the fucoidan-coated multifunctional nanozyme targeting tumor vascular sites, which is a self-enhanced red light carbon dot composite system targeting tumor vascular sites.

[0016] Preferably, in step (1), the muffle furnace temperature is set at 120-200° C., the reaction time is 1-6 h, the volume ratio of the reaction stock solution to ethanol is 1:4-1:6, and the centrifugal speed is 6000-10000 rpm.

[0017] Preferably, the mass ratio is citric acid:urea:disodium EDTA:metal ion=4:8:1:0.5-12:24:3:1.

[0018] Preferably, in step (2), the mass ratio of the metal ion-doped carbon dot nanozyme to the glucose oxidase is 1:1 to 7:1, and the reaction time is 6 to 12 hours.

[0019] Preferably, in step (3), the mass ratio of arginine to the carbon dot-glucose oxidase complex system is 1:1 to 1:7, and the reaction time is 1 to 12 hours.

[0020] Preferably, in step (4), the mass ratio of the composite system of fucoidan and arginine coating is 1:2 to 5:1, and the reaction time is 1 to 12 hours. Fucoidan coating on the surface of the system achieves targeting of activated vascular endothelial cells.

[0021] The invention relates to the application of the self-enhanced red light carbon dot composite system targeting tumor blood vessels in the preparation of multi-modal synergistic tumor therapeutic drugs and drug targeted delivery systems.

[0022] The present invention first synthesizes metal ion-doped carbon dot nanozymes, then uses the self-assembly principle to complex the metal ion-doped carbon dot nanozymes with glucose oxidase, and loads arginine to make the surface of the complex positively charged while the system can achieve gas therapy. Subsequently, fucoidan is coated on the surface of the system to achieve vascular targeting of the tumor site.

[0023] Among them, preferably, Fe 3+ As doped metal ions, red light carbon dots with nanozyme activity were constructed. The excitation wavelength of the carbon dots is 560nm, the emission wavelength is 610nm, and the particle size is about 3.2nm. It can emit red fluorescence to achieve a tracing effect. 3+Ion doping endows the carbon dots with excellent peroxidase (POD), superoxide dismutase (SOD), and glutathione oxidase (GSH-OXD)-like activities, as well as excellent photothermal conversion capabilities. The carbon dots can generate large amounts of strongly oxidized ·OH through a cascade reaction of SOD- and POD-like enzymes. Meanwhile, the POD-like enzyme utilizes hydrogen peroxide to generate ·OH. To achieve the supply of hydrogen peroxide, glucose oxidase is complexed with the carbon dots, which consumes glucose and produces hydrogen peroxide, thereby producing more ·OH while simultaneously providing starvation therapy.

[0024] The introduction of arginine into the composite system not only enables the system to perform gas therapy, but also makes the surface of the composite positively charged, which is beneficial for the subsequent coating of fucoidan. At the same time, due to electrostatic forces, the system can be depolymerized in an acidic environment. Fucoidan, as a targeting ligand for targeting blood vessels in the tumor site, can bind to the P-selectin receptor highly expressed on activated vascular endothelial cells. After the system achieves initial targeting, the system will depolymerize and release the carbon dot-glucose oxidase complex system and arginine under the action of the slightly acidic environment of the tumor and the temperature increase caused by photothermal treatment. The system then consumes glucose in the tumor site and produces ROS such as hydrogen peroxide and ·OH, as well as NO. While achieving photothermal therapy / cascade catalytic therapy / gas therapy to kill the tumor, ROS stimulate the activation of non-activated vascular endothelial cells in the tumor site and provide more targets for subsequent preparations, thereby achieving self-enhanced tumor vascular site targeting.

[0025] Beneficial effects of the present invention:

[0026] (1) The carbon dot nanozyme constructed in the present invention has POD enzyme-like, SOD enzyme-like, and GSH-OXD enzyme-like activities, which can enhance oxidative stress in tumor sites and greatly improve the nanozyme-mediated cascade catalytic anti-tumor therapeutic effect. At the same time, due to its red light emission characteristics, it can achieve fluorescent tracing of tumor sites.

[0027] (2) The present invention can achieve vascular targeting of tumor sites through the fucoidan coated on the outside of the system. At the same time, the system can responsively depolymerize to generate ROS and stimulate the activation of surrounding cells, thereby providing more targets for subsequent preparations to achieve self-enhanced targeting. In vivo pharmacodynamic studies have revealed that under the multiple effects of cascade catalytic therapy mediated by nanozymes and natural enzymes, photothermal therapy, and gas therapy, tumor growth is severely inhibited, achieving a synergistic tumor treatment with multiple treatments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the transmission electron microscopy image of Fe(III)-CDs prepared in Example 1.

[0029] Figure 2This is a transmission electron microscope image of FG prepared in Example 2.

[0030] Figure 3 This is the UV-visible spectrum of FGA@Fu prepared in Example 3.

[0031] Figure 4 Fourier transform infrared spectra of Fe(III)-CDs, FG(a) and FGA@Fu(b) prepared in Example 1, Example 2 and Example 3.

[0032] Figure 5 This is the transmission electron microscopy image of FGA@Fu prepared in Example 3.

[0033] Figure 6 Transmission electron microscopy image (a) and laser particle size analyzer result (b) of the depolymerization of FGA@Fu prepared in Example 3.

[0034] Figure 7 These are the temperature increase effect curves of Fe(III)-CDs, FG and FGA@Fu prepared in Examples 1, 2 and 3.

[0035] Figure 8 The fluorescence properties of Fe(III)-CDs, FG and FGA@Fu prepared in Examples 1, 2 and 3.

[0036] Figure 9 The cytotoxicity of Fe(III)-CDs, FG and FGA@Fu prepared in Example 1, Example 2 and Example 3.

[0037] Figure 10 The cellular uptake effects of Fe(III)-CDs, FG and FGA@Fu prepared in Examples 1, 2 and 3.

[0038] Figure 11 These are diagrams showing the intracellular ROS production effects of Fe(III)-CDs, FG, and FGA@Fu prepared in Examples 1, 2, and 3.

[0039] Figure 12 The activation effects of Fe(III)-CDs, FG and FGA@Fu prepared in Examples 1, 2 and 3 on HUVECs vascular endothelial cells.

[0040] Figure 13 (a) Mouse tumor growth curve, (b) Mouse weight change curve, (c) Tumor photo and (d) Tumor anatomical mass of Fe(III)-CDs, FG and FGA@Fu prepared in Example 1, Example 2 and Example 3. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the disclosure of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalents fall within the scope limited by the appended claims of the application.

[0042] Example 1

[0043] Preparation and characterization of Fe(Ⅲ)-CDs

[0044] (1) Preparation of Fe(III)-CDs

[0045] 2.0 g of citric acid, 4.0 g of urea, 0.5 g of disodium ethylenediaminetetraacetic acid, and 0.35 g of ferric chloride hexahydrate were weighed and dissolved in 20 mL of formic acid solution. The mixture was stirred for 25 minutes and then transferred to a 50 mL polytetrafluoroethylene-stainless steel reactor. The reactor was placed in a muffle furnace and reacted at 160°C for 4 hours. The reaction mixture was then cooled to room temperature. After the reaction, the reaction solution was mixed with 5 volumes of anhydrous ethanol and centrifuged at 10,000 rpm for 5 minutes to collect the precipitate. This process was repeated three times to obtain a black solid, Fe(III)-CDs.

[0046] (2) Characterization of Fe(Ⅲ)-CDs

[0047] The particle size of the metal ion-doped carbon dot nanozyme (abbreviated as carbon dot) was measured using transmission electron microscopy. Figure 1 As shown in Figure 2, the average particle size of the carbon dots is 3.16 nm, and the particle size distribution is uniform. High-resolution transmission electron microscopy shows that the carbon dots have obvious lattice fringes. The lattice spacing is similar to that of graphite sp 2 The interplanar spacing of the hybrid carbon is consistent, indicating a graphite-like structure. The above proves that the Fe(Ⅲ)-CDs were successfully prepared.

[0048] Example 2

[0049] Preparation of FG (carbon dot-glucose oxidase composite system)

[0050] 20 mg of carbon dots were dispersed in 25 mL of pH 7.4 PBS. 5 mL of a 1 mg / mL glucose oxidase solution was added dropwise. After stirring at room temperature for 4 hours, the reaction solution was transferred to a 50 kDa ultrafiltration centrifuge tube and centrifuged at 5000 rpm for 5 minutes. The nanoparticles in the inner tube and the solution in the outer tube were collected. This process was repeated three times. Finally, the solid material in the inner tube was removed to obtain the FG (carbon dot-glucose oxidase complex).

[0051] The particle size of the FG (carbon dot-glucose oxidase composite system) was measured using transmission electron microscopy, and the results are shown in the attached figure. Figure 2 As shown, the average particle size of the composite is 29.9 nm.

[0052] Example 3

[0053] Preparation of FGA@Fu

[0054] 10 mg of FG complex was dispersed in 2 mL of pH 7.4 PBS and added dropwise to 10 mL of 0.5 mg / mL arginine solution. After stirring at room temperature for 6 hours, the reaction solution was transferred to a 50 kDa ultrafiltration centrifuge tube and centrifuged at 5000 rpm for 5 minutes. The nanoparticles in the inner tube and the solution in the outer tube were collected. This process was repeated three times. Finally, the solid material in the inner tube was removed, which was the FGA (carbon dot-glucose oxidase-arginine complex).

[0055] 10 mg of FGA complex was dispersed in 2 mL of pH 7.4 PBS and added dropwise to 10 mL of a 1 mg / mL fucoidan solution. After stirring at room temperature for 6 hours, the reaction solution was transferred to a 50 kDa ultrafiltration centrifuge tube and centrifuged at 5000 rpm for 5 minutes. The nanoparticles in the inner tube and the solution in the outer tube were collected. This process was repeated three times. Finally, the solid material in the inner tube was removed, which was FGA@Fu.

[0056] UV-visible spectroscopy and Fourier transform infrared spectroscopy were used to characterize FGA and FGA@Fu to verify the loading of arginine and the coating of fucoidan. The results are shown in the attached figure. Figure 3 、 4 shown.

[0057] The particle size of FGA@Fu composite was measured by transmission electron microscopy. Figure 5 As shown, the average particle size of the composite is 95.2 nm.

[0058] FGA@Fu was dispersed in pH 5.0 PBS and irradiated with NIR laser for 5 min. The dissociation of the system was detected by transmission electron microscopy and laser particle size analyzer. The results are shown in the attached figure. Figure 6 As shown, FGA@Fu can be depolymerized in a slightly acidic environment and under NIR irradiation.

[0059] Example 4

[0060] The photothermal performance of carbon dots and FGA@Fu was evaluated by irradiating them with NIR laser. Figure 7 As shown, carbon dots and FGA@Fu have a good temperature-raising effect.

[0061] Example 5

[0062] The fluorescence properties of carbon dots and FGA@Fu were characterized by using an enzyme-labeled instrument. Figure 8As shown in the figure, the emission peaks of the carbon dots and FG composite system are at 630 nm, while FGA and FGA@Fu have stronger emission light with emission peaks at 610 nm, and both can emit red fluorescence.

[0063] Example 6

[0064] In vitro cytotoxicity of the complex system against 4T1 tumor cells

[0065] 4T1 tumor cells in the logarithmic growth phase were taken and 5×10 3 The cells were seeded at a density of 100 μg / well in a 96-well plate, with 5 replicate wells per group. The cells were cultured in a 37°C, 5% CO2 cell culture incubator. After the cells attached to the wall, they were incubated with 1640 cell culture medium containing Fe(Ⅲ)-CDs, GOx, FG, and FGA@Fu for 24 h. For the NIR laser irradiation group, after incubation for 12 h, 1.0 W / cm 2 The cells were irradiated with a laser power of 100 nm for 3 min. The concentrations of GOx were 0.01, 0.05, 0.1, 0.5, and 1.0 μg / mL (the concentrations of the remaining groups were converted to the concentrations of the GOx group). After the incubation, 20 μL of 5 mg / mL MTT solution was added to each well and incubated in a cell culture incubator at 37°C and 5% CO2 for 4 h. The solution in the 96-well plate was discarded, and 200 μL of dimethyl sulfoxide solution was added to each well. The plates were shaken on an oscillator for 10 min, and the absorbance of each well was measured at 570 nm in a microplate reader to calculate the cell survival rate. The results are shown in the attached figure. Figure 9 As shown in the results, Fe(Ⅲ)-CDs alone did not produce obvious cytotoxicity to 4T1 cells, and the FG group significantly reduced the survival rate of 4T1 cells. At the same time, NIR laser irradiation further reduced the survival rate of 4T1 cells.

[0066] Example 7

[0067] Uptake of the complex system in 4T1 cells

[0068] 4T1 cells in the logarithmic growth phase were cultured at 10 5 Cells were seeded into 24-well plates with slides and cultured for 12 hours. Fe(Ⅲ)-CDs, GOx-FITC, FG, and FGA@Fu suspensions prepared with FBS-free 1640 cell culture medium were added to make the final concentration of GOx 0.05μg / mL. The cells were cultured for 2 hours. The cells were washed 3 times with PBS. 400μL of 4% paraformaldehyde was added and incubated at room temperature for 15min. The cells were washed 3 times with PBS. 100μL of Hoechst (10μg / mL) was added and incubated at 37℃ for 10min. The cells were washed 3 times with PBS. The slides were inverted on a glass slide with mounting solution and observed under CLSM microscope. The results are shown in the attached figure. Figure 10As shown in the figure, red represents the red fluorescence of carbon dots, and green represents the fluorescence of FITC-labeled glucose oxidase. It can be seen that carbon dots can increase the cellular uptake of GOx after forming FG complexes with GOx, and NIR laser irradiation also increases the cellular uptake of the system.

[0069] Example 8

[0070] Intracellular reactive oxygen species production in the composite system

[0071] 4T1 tumor cells in the logarithmic growth phase were inoculated into a 24-well plate with a cell slide. After incubation for 24 h, the culture medium was replaced with 1640 cell culture medium containing Fe(Ⅲ)-CDs, GOx, FG, and FGA@Fu and incubated for 4 h. After the incubation, the NIR laser irradiation group was irradiated with 1.0 W / cm 2 The cells were irradiated with a laser power of 100 nm for 3 minutes. After the incubation, the culture medium was discarded and the cells were washed with PBS three times. 500 μL of 10 μM DCFH-DA dye solution was added and incubated for 30 minutes to stain the intracellular reactive oxygen species. After the incubation, the cells were washed with PBS three times and 500 μL of 10 μg / mL Hoechst dye solution was added and incubated for 15 minutes to stain the cell nuclei. After the staining, the cells were washed with PBS three times and sealed with anti-fluorescence quenching sealing solution. The cells were then placed under a confocal laser microscope for fluorescence imaging. The results are shown in the attached figure. Figure 11 As shown, the green fluorescence of the FG complex-treated group was significantly higher than that of the other nanozyme groups. At the same time, NIR laser irradiation further enhanced the production of intracellular reactive oxygen species, indicating that FGA@Fu has excellent intracellular reactive oxygen species production ability.

[0072] Example 9

[0073] Activation effect of the composite system on endothelial cells

[0074] HUVECs vascular endothelial cells in the logarithmic growth phase were seeded in a 24-well plate with a cell slide. After incubation for 24 h, the culture medium was replaced with 1640 cell culture medium containing 4T1 cell supernatant, Fe(Ⅲ)-CDs, GOx, FG, and FGA@Fu for 4 h. After the incubation, the NIR laser irradiation group was irradiated with 1.0 W / cm 2The cells were irradiated with a laser power of 100 nm for 3 minutes. After incubation, the culture medium was discarded and the cells were washed three times with PBS. The primary antibody CD62P was added to bind to P-selectin and then washed three times with PBS. FITC-labeled fluorescent secondary antibody was then added. After incubation, the cells were washed three times with PBS. 500 μL of 10 μg / mL Hoechst staining solution was added and incubated for 15 minutes to stain the cell nuclei. After staining, the cells were washed three times with PBS and sealed with anti-fluorescence quenching sealing solution. The slides were then placed under a confocal laser microscope for fluorescence imaging. The results are shown in the attached figure. Figure 12 As shown, the untreated group showed almost no green fluorescence, while the green fluorescence of the FG complex-treated group was almost identical to that of the 4T1 supernatant group, indicating that the FG complex can activate endothelial cells to the same degree as the 4T1 supernatant. Furthermore, NIR laser irradiation further enhanced the degree of endothelial cell activation, demonstrating that FGA@Fu has excellent endothelial cell activation capabilities.

[0075] Example 10

[0076] The composite system is used to treat tumors in mice

[0077] 4T1 tumor cells in the logarithmic growth phase were taken and 1×10 6 The cells were inoculated subcutaneously at a density of 1 / mouse. The tumor volume of the mice was about 100 mm. 3 At the same time, mice were randomly divided into normal saline, Fe(Ⅲ)-CDs, FG, FGA@Fu, and FGA@Fu+NIR groups. Nanozymes in each group were diluted and intravenously injected into mice at a concentration of 100 μL 20 mg / kg per mouse. The dose was administered once every two days for a total of three times. The changes in mouse body weight and tumor volume were recorded every other day during the treatment period. The results are shown in the attached figure. Figure 13 As shown in the figure, compared with the saline group, each composite system treatment group had a certain degree of inhibitory effect on the growth of mouse tumors. At the same time, after NIR laser irradiation, the tumor inhibition effect of FGA@Fu was further enhanced, and the tumor volume showed a significant reduction trend.

[0078] The above description is only the best specific implementation method of the present invention, but the scope of protection of the present invention is not limited to this. Any modifications, equivalent replacements and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention should be included in the scope of protection of the invention.

Claims

1. A self-enhanced carbon dot composite system targeting tumor blood vessels, characterized in that: It is composed of photothermal-responsive carbon dot nanozymes, glucose oxidase, tumor-site vascular targeting ligands and arginine.

2. The self-enhanced tumor vascular targeting carbon dot composite system according to claim 1, characterized in that: The self-enhanced tumor vascular targeted carbon dot composite system has pH-responsive drug release capability and synergistic enhancement of photothermal therapy, cascade catalytic therapy, and gas therapy under near-infrared irradiation.

3. The self-enhanced tumor vascular targeting carbon dot composite system according to claim 1, characterized in that: The photothermal responsive carbon dot nanozyme is prepared by carbonization polymerization of citric acid, urea, disodium ethylenediaminetetraacetic acid, and metal ions, wherein the metal ions are Cu + 、Cu 2+ 、Fe 2+ 、Fe 3+ 、Mn 2+ One of them.

4. The self-enhanced tumor vascular targeting carbon dot composite system according to claim 1, characterized in that: The tumor site vascular targeting ligand is fucoidan, which is coated on the surface of the system to achieve targeting of activated vascular endothelial cells.

5. The method for preparing a self-enhanced tumor vascular targeting carbon dot composite system according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Dissolving citric acid, urea, disodium ethylenediaminetetraacetic acid, and a metal ion precursor in a formic acid solution, ultrasonically dispersing the mixture evenly, and placing the mixture in a polytetrafluoroethylene bottle, which is then placed in a muffle furnace for reaction. After the reaction is complete, the reaction solution is mixed with ethanol and centrifuged, and the supernatant is discarded and the precipitate is collected to obtain a metal ion-doped carbon dot nanozyme. (2) The metal ion-doped carbon dot nanozyme is mixed with glucose oxidase, and the unreacted metal ion-doped carbon dot nanozyme is removed by centrifugal ultrafiltration to obtain a carbon dot-glucose oxidase composite system; (3) The carbon dot-glucose oxidase composite system is added to the arginine solution, mixed evenly, and then ultrafiltered to obtain the arginine-coated composite system; (4) The arginine-coated composite system was added to the fucoidan solution and incubated together before ultrafiltration to obtain a self-enhanced red light-emitting carbon dot composite system targeting tumor blood vessels.

6. The method for preparing a self-enhanced tumor vascular targeting carbon dot composite system according to claim 5, characterized in that: In step (1), the muffle furnace temperature is set at 120-200° C., the reaction time is 1-6 h, the volume ratio of the reaction stock solution to ethanol is 1:4-1:6, and the centrifugal speed is 6000-10000 rpm.

7. The method for preparing a self-enhanced tumor vascular targeting carbon dot composite system according to claim 5, characterized in that: In step (2), the mass ratio of the metal ion-doped carbon dot nanozyme to the glucose oxidase is 1:1 to 7:1, and the reaction time is 6 to 12 hours.

8. The method for preparing a self-enhanced tumor vascular targeting carbon dot composite system according to claim 5, characterized in that: In step (3), the mass ratio of arginine to the carbon dot-glucose oxidase complex system is 1:1 to 1:7, and the reaction time is 1 to 12 hours.

9. The method for preparing a self-enhanced tumor vascular targeting carbon dot composite system according to claim 5, characterized in that: In step (4), the mass ratio of the composite system of fucoidan and arginine surface modification is 1:2 to 5:1, and the reaction time is 1 to 12 hours.

10. Use of the self-enhanced tumor vascular targeted carbon dot composite system according to any one of claims 1 to 4 in the preparation of multimodal synergistic tumor therapeutic drugs and drug targeted delivery systems.

Images